Why didn't AIDS spread
throughout the world, and particularly throughout Africa, in
antiquity as it does now? To explain that let us look at the
publications of travellers of the 19th and 20th centuries.
From those works it becomes understandable that until the end of the
19th century the majority of regions in the African continent were
almost isolated from each other. Dangerous tropical jungles,
torrential rivers, wide deserts, attacks by aggressive tribes etc.
were obstacles to migration.

But the most important barriers
were the many epidemic diseases: malaria, dysentery, smallpox, yellow
fever and others. It's possible that in separate tropical regions
the inhabitants became ill and died as a result of AIDS, but the absence
of constant ties to other regions would prevent the spread of the
infection....

In the 2nd half of the 20th
century events occurred which could have accelerated the spread of AIDS.
The first was an explosion of migration. According to UNESCO today
around 100 million people live outside their homeland.

First
published in this format in Nova Irlanda Esperantisto No 65 2004